Speaker
Description
With the completion of the early phase of the FERMI 2.0 upgrade program, the FERMI facility has significantly increased its flexibility, enabling an important extension of its operational capabilities. The redefined FEL-1 layout, supporting both HGHG and EEHG operation modes, has substantially broadened the FEL-1 tuning range. This advancement is accompanied by improved spectral brightness and enhanced stability, achieved through the now reliable implementation of EEHG, which is also available for user operation.
In parallel, the upgrade of the FERMI linac—through the installation of new high-gradient S-band accelerating cavities—has enabled routine operation at higher electron beam energies. This has been effectively exploited to extend the FEL-2 tuning range toward higher photon energies. Furthermore, developments in the seed laser system have enabled preliminary experiments with seeding at 200 nm, further enhancing short-wavelength operation capabilities.
By leveraging these advancements, operation at the nitrogen and oxygen absorption edges has been successfully demonstrated, and measurements have confirmed the generation of higher harmonics extending beyond 1 keV.
These results demonstrate that the current machine configuration is already capable of meeting the growing demand from the scientific user community for stable, coherent radiation in this spectral range. At the same time, they provide essential input for guiding the next phases toward the full realization of the FERMI 2.0 upgrade program.